Table 26. System-board-assembly LEDs description (continued)
LED
Description
Action
4.  If the problem still remains, contact Lenovo 
Support.
5  FPGA heartbeat 
LED (green)
The FPGA heartbeat LED helps 
you identify the FPGA status. 
•  Blinking (1Hz) : FPGA is 
working normally.
•  On or off: FPGA is not 
working.
If the FPGA heartbeat LED is always off or always on, do 
the following:
1.  Replace the processor board.
2.  If the problem remains, contact Lenovo Support.
6  DIMM error LED 
(yellow)
LED on: an error has occurred to 
the DIMM the LED represents. 
For more information, see 
“Memory problems” on page 
206
.
LEDs on the firmware and RoT security module
The following illustrations show the light-emitting diodes (LEDs) on the ThinkSystem V3 Firmware and Root 
of Trust Security Module (firmware and RoT security module). 
Figure 131. LEDs on the firmware and RoT security module
1  AP0 LED (Green) 2  AP1 LED (Green) 3  Fatal Error LED (Amber)
Table 27.  LEDs description
Scenario AP0 LED AP1 LED 
Fatal 
Error 
LED
FPGA 
heart-
beat 
LED
note
XCC 
heart-
beat 
LED
note
Actions
RoT security module 
fatal firmware failure
Off Off On N/A N/A Replace the firmware and RoT 
security module.
Blink N/A On N/A N/A Replace the firmware and RoT 
security module.
Blink
N/A On On N/A Replace the firmware and RoT 
security module.
198 ThinkSystem SR645 V3 User Guide